Screw making machine



March 21, 1933.

R. s. CROSBY ET A1.

SCREW MAKING MACHINE 4 Shee'cS-Sheei'I l Filed Dec. 19 1927 Mardi 21 1933. R. s. CROSBY ET Al.

SCREW MAKING MACHINE Filed Dec. 19, 192'! 4 Sheets-Sheet 2 2 E i 0 ATTg/YEY March 21, 1933.

R. S. CROSBY El' AL SCREW MAKING' MACHINE Filed Dec. 19, 1927 4 Sheets-Sheet 5 4 Sheets-Sheet 4 R. S. CROSBY ET AL SCREW MAKING MACHINE Filed Dec.

March 21, 1933.

Patented Mar. 21, 1933 PATENT ori-ieu e. g

REUBEN s. CROSBY, or HARTFORD, ANn'CHAn-Lns W. sroNsEI.,v OF WETIIERSFIELD,

CCNNECTIOUT, AssIGNOns TO THEAsA s. COOK COMPANY, or HARTFORD., CON- NECTICUT, A CORPORATION OF CONNECTICUT I SCREW MAKING MACHINE Application mea December 19, 1927. Lserial No.' 241,008.

Our invention relates to that'class of ma-v chines that are employed for cuttingthreads on screw blanks, and an object of the invention, among others, is the provision oi mechanism which will materially reduce the time required for cutting the threads, particularly on wood screws, so-called, and thereby greatly increase the Output of such machines. y

One form of machine embodying this invention and in the construction and use of which the objects herein set out, as well as others, may be attained, is illustrated in the ccompanying drawings, in which- Figure 1 is an'isome'tric view of the tool supporting part of the tool operating mechanism ot our improved machine. f

Figure 2 is a top view-of one end of our improved machine, with parts .broken away to show construction and with 'the driving j spindle and some of the gears omitted.

Figure 3 is a view in section on a plane denoted b y the dotted line 3*-3 of Figure 2.. Figure a1- is a view 1n elevation of a portion` of one end oi our improved machine.y

Figure 5 is a view in section on a plane denoted by the dotted line 5-'5 of Figure 2, parts beyond being omitted.

Figure 6 is a view in section on a plane denoted by the dotted line 6 6 of Figure 2, parts beyond being omitted.

Figure' T is a detail view illustrating the construction of the rocker frame operating lever, with parts broken away to show construction. A y

Figure 8 is a view in section on a plane-denoted by the dotted line 8-8 'of Figure 9. y

Figure 9 is a 'view in front elevation of a portion of the rocker frame and of one tool post. n

Figure 1 is on a scale enlarged over that of Figures 2 to 9. f i

Figures 10, 11 and 12 are, respectively,

iront, side and isometric views of a modilied structure for holding the tool fixtures shoe e ainst its cam plates. .c

.J gure 18 is a top view similar to Figure but showing more ot themechanism.

Figure l14 is a view in section .on a plane denoted by the dottedline 1li- 14 of Figure 13.

clear understanding of the invention.

Figure 15 is a diagrammatic view illus-` trating the construction and operation of the cams and parts actuatedgthereby. Y. y

In the accompanying drawings the numeral indicates the rameof our improved machine that may be supported in any suitable manner, as by legs 11, said frame including intermediate and end supports extending crosswise of the trame and in which various parts of the mechanism are mounted. A cam shaft 13 is mounted in the supports 12 and is connected vas by'meansV of a. trainof gears 14 with a driving spindle valso mountedin the supports 12 and'driven as by means of a belt 16 that may extend'from 'an electric'motor or other suitable source of power, not herein shown. ,Said spindle is Vprovided; with a chuck 9 or other means Jfor holding a screw blank 17, but as such holding means are common to machinesl of this class and therefore well understood by those skilled in the art a detailed description Vand illustration,V are omit-ted herein.

A tool supporting bar 18 is mounted for reciprocating movement in the supports 12, the support for one end of said bar, however, not being shown herein as it is not necessary to a This bar has a tip 19 set into itsV end for Contact with a traversing member that is herein shown in the form of a cam 2O to impart reciprocating movement to the tool bar, said cam being secured toa shatt- 21'mounted intwoof the supports 12. v .y

Uur invention comprises means for etfectin gadoublecut in a groove in a screw blank at each reciprocating'movementof' the tool supporting bar, and this Vwe accomplish by the mechanism shown herein, and which may be embodied in several different formstoattain the desired end. In this arrangement we` mount two tools on the bar 18 spaced apart sov that they will Operateside by side and simultaneously inthe same groove but on opposite sides of the rib dividing adjacent sections'of said groove, and the mechanism is so constructed that the tools will be brought into Contact with the screw blank at proper v times to accomplish the desired end.

In this arrangement a tool post 22 having a suitable clamp for securing a cutting tool 23 therein is secured to the bar 18 and another tool post 24 having a suitable clamp forsecuring a cutting tool 25V therein is loosely mounted on saidvbar to turn independently thereon. A spacing block 26 is secured to the bar 18 and has a tool Vpost supporting lip 27' in contact with the side ofthe tool post 24 for the purpose of supporting said post in its movements to engage the tool25 with a screw blank, and also while said tool isoperating upon the blank. `The tool post 24 has an arm 28 projecting therefrom and witha shoe 29 adjustably secured thereto for varying the depth of the cut, the lower end of the shoe ridingupon the cam plates to be hereinafter described.

A rocker frame 30 is mounted for rocking movement upon the bar 18 `and upon a stud 31 projecting from one of the supports 12 and as shown in Figure 2 of the drawings. This frame is of generally U-shape with one arm supported upon said bar and the other arm supported upon the stud. The frame also comprises a cam plate supporting arm 32 and an actuating lever supporting arm 33 with a cross bar 34 connecting the two branches of the Jframe, and as shown` in Figure 2. The arm 32 has a thread cutting cam'plate 35 and a pointing cam plate 36 secured to it, and as shown in Figure 1, the plate 35 being secured against the arm and the plate 36 being secured against the plate 35. These plates are secured as by bolts 37 passing through slotsin the plates, and as shown in dotted lines in Figure 9, and by means of which the position of the pla-tes on'the arm may be adjusted.

A thread cutting cam plate 38 is secured to A the under side of the cross bar 34, and as shown particularly in Figures 1, 5 and 6, and is adapted to be engaged by a shoe ona thread cutting arm 39 secured to and proj ectingfrom the bar 18. The cam plates 35 and 36 operate to throw the tool post 24 with its tool 25 into cutting engagement with the screw blank 17, said post rotating upon the bar 18 as hereinbefore described. The cam plate 38 is for the purpose of actuating the arm 39 and hence the bar 18 to rock the latter and move the tool post 22 so that the tool 23 thereon will engage the screw blank. These cams arei'ormed 'to engage the tools with the screw blank at the proper time, the tool 25 being actuated by the pointing cam plate 36 to round the point on the blank after the tool 23 has passed beyond such point.

In operation' to cut a thread the cutting tool 23 is first engaged with the screw blank by the actionof the cam plate 38, as the bar 18 ismoved endwise'by the cam 20. Vhen a' groove hasbeen cut entirely around the screw blank, as shown in Figure 1, by the tool 23 the shoe 29 on the arm 28 engages the cam on the bar 35 thus rocking the tool post 24 to engage its tool 25 within and atk the beginning of the groove just cut by the tool 23, the tool 25 being rocked inwardly far enough to cut the groove deeper, and in this operation the tool post 24 rotating on the bar 18 as hereinbefore described. As the bar 18 continues'its movement the tool 23 will pass beyond the pointed end of the blank 17 and immediately thereafter the shoe 29A will vengage the cam on the plate 36, thus rocking the tool 25 rapidly inward to'round and form the point on the blank.

I'Vhen the operation just described is completed the cam 2O is shaped to permit the bar 18 to be returned rapidly to its starting point, as by means of a spring 43 that is so attached to the bar as to force it into engagement with the cam, and also as to exert a torsional force thereon to hold the thread cutting arm 39 in contact with the cam 38. Just before this return movement a rocker frame actuating lever 40 adjustably pivotally mounted on the arm 33 of the rocker frame is located opposite a depressionin a tool disengaging cam 41 secured to the shaft 13 which permits the rocker frame to be actuated as by a spring 42 to move both toolsaway from the screw blank after the return movement of said tools carried by the bar 18 to their initial or starting point, when the operation will be repeated. In this operation it will be noted that the two tool posts and the supporting Vlip 27 are moved away from the screw blank together so that there is wear upon said lip only when the tool post 24 is moved toward the screw blank.

The actuating lever 40 is adj ustably mounted on the arm 33,'as byv means of an adjusting screw 44 by means of which the position of the cam plates 35 and 36 may be changed with reference to the cam 41.

In Figures 10 to 12 (Sheet I of the drawings) there is shown a modification of the structure for holding the shoe 29 against thecam plates 35-36. In this structure a bracket including arms 45` and a base 46 is secured to the cam plate supporting arm 32 and a' presser is pivotally mounted in said arms. This presser comprises a presser arm 47 and a presser plate 48 formed of a single v piece.' The arm 47 receives the pressure of a presser spring 49 located in a socket 50 forming an integral part of the bracket, hereinbefore referred to, said spring projecting out of said socket against the back of said arm, and as shown in Figure 11 of the drawings. This spring acts to holda lip on the plate 48 in contact with a roller 51 mounted von a screwA stud secured in the end of the arm 28. said roller rotating in contact with the under edge of said lip as the arm 28 is reciprocated in the operation of the bar 18.

The blanks 17 are supplied to the chuck 9 from a hopper (not shown) and by the operation o feed fingers, which are also omitted in the drawings, such hopper and feed fingers being common to machines'of this class and for which (reason affurther and detailed description is not given asthe construction and operation thereof willbe readily understood by those skilled in theart. VIt is, however, shown that said feed fingers are operated by a rocking feed finger lever, which lever includes a rock shaft (notshown) and a tail. 52 in contact with and operated by a feed finger operating cam 53 secured to the cam shaft 21. This lcam has two depressions 54-55, thedepression 54 operating the lever to cause the fingers tograsp the blanks and thedepr'ession 55 operating said fingers and lever to place the blanks in line vwith the opening between the jaws of the chuck 9.V The cam just described and the depressions 54--55 therein permit the tail 52 of the feed finger operating lever, and the feed fingers connected therewith, to move forward under the influence of a `spring arranged in any ordinary manner to hold thetail of the lever against the cam. This spring is not shown but itsarrangement and operation will be readily understood by those skilled in the operation of lmachines of this kind.'

When the blanks are positioned in front of the chuck as just described, they are pushed into the openingbetween the chuckjaws by a pointing tool 56 that engages the ends of the'v blanks and moves them forward. This pointing tool is yieldingly mounted on and s upported by a pointing tool slide 57 operatively engaged with a pointing tool actuator 58 mounted for rocking movement in the frame, and as shown in Figure 13. This actuator is operated by a cam 59 secured to the camshaft 21. The actuator 58 is held against the caniv as by means of aspring 60and the cam 59 is formed to positively move the slide 57 backward should for any reason 'the spring 60 fail to act.

A back rest 61 is pivotally` mounted by means of a shaft 62 on the frame of the machine,'this back rest being actuated by means of a cam 63 formed on the slide 57, and as shown in Figure 13.

When a blank has been placed between the chuck jaws the latter are operated tov grasp the blank in a common and'well known manner by a collar 64 engaged by an arm 65 on a chuck operating bar 66 mounted in the frame, and as shown in Figure 13. The bar 66isactuated by engagement of a stud 67 thereon with a chuck operating cam 68 on the shaft 21. When the blank has been grasped by the chuck the pointer is given a slight'further advance movement to point the blank land .is

= then moved back by the action ofthe spring 60and cam V59,7the backrest is movedby the cam 63 to support the blank and cams 4l and 20 function as hereinbefore described to actuate the threading tools to perform their operations after which the chuck j awsare actuated to release the'. blankk for arepetition of the operation lof the machine. v

`A very important feature of thisinvention Y resides in that arrangement whereby maximum speed, and therefore production, is obtained, the different elements being gradually moved to 'a location adjacent to the point of Y action, while other membe'rsare performing their operations, thus being inreadi'ness to promptly take up their work as soon as the other parts finish and move out ofthe wayand-without loss of time in arriving at the point of'action. -This is graphically illustrated in Figure 15V wherein a development of the cams ina straight line is shown, the beginning of a cycle ofoperations ofthe lmachine being'at thevpoints on the cam denoted by the dotted line a. At this point the tail 52 of the feed finger operating lever is just ready to drop in to the depression 54, the pointer actuator 58 Vis in position with the pointer at its rearward limit ofmove- Y 67 is in the position assumed when the chuck jaws are closedf'The tip 19 of theba'r 18 is advancing up the incline of the cam 20 to pass f the'cutting toolsalong the blank in the cutting operation'. l Y

Now. 'as the tail 52drops into the depression 54l the feed fingers are advanced to pick up arblank fordelivery to the chuck, and im'- mediately passing outof said depressionsaid fingers move slightly backward to. permita blank supplying member (notshown) and Y from which the blank was obtained from the feed fingers, tomove out ofthe way. During this interval the action of'all of the other parts is unchanged. At about the time the tail 52 leaves the depression 54 the rocker frame actuating lever suddenly drops into a depression in the cam 41 at the point indicated by the dotted line b and the cutting tools are moved away from', the blank, having completed their cutting operatiomf but the 'advance of said cuttingtools along the blank continues until the cam reaches the point indicated by the dotted line c, this to accommodate blanks of greater length when such shall be desired. It is here observed that in the arrangement `herein shown the camf20 makes four complete rotations to a single rotation of each of the other cams, this single rotation of the other camsl being'defined by the length of cainsurface shown in this figure 15. This increased speed of the cam 2O is obtained byV the gear train hereinbefore referred to. Different speeds may be given to this cam 2O by a change in the gear ratios and to effect the cutting of screws of different sizes.V l From the point indicated by the dotted v pointer.

an inclined portion on the cam to move the cutting tools to a point to begin another cutting operation, but at' this point the cam' 2O` makes an ineii'ective rotation, the cutting tools being advanced along the blank but remaining out of contact with it. This occupies but a brief interval in the operation of the machin'e and is for the purpose kof permitting the placing of a new blank inthe chuck. During this movement of the cam 20, just described, the 'cam 59 reaches a point indicated by the dotted line d, at which point a slight incline upwardly on thecam begins.- This starts a slow forward movement of the As the cams advance the cam 53' reaches a peint denoted by the dotted line c at the edge of the depression 55 and in'the continuing movement of the cams the tail 52 drops into said depression, thereby moving the feed finger lever i and the-feed lingers forward to position the blank in said fingers in line-with the chuck 9. During this movement of the cam the cam 59 reaches a point denoted by the dotted line f whereat thecam surface on said cam inclines rapidly upwardly thereby moving the pointer 56 rapidly forward to a position close to the end of the blank inreadiness for prompt action thereon. At the point indicated by the dotted line g the cam is formedv to causeda dwell in the action of the tool'and -thepointer therefore remains j stationary but in readiness for prompt action, this dwell `being for the purpose of permitting the back rest 61 to move out of the way,"such movement being-effected by the action of the camv 63 caused by j thepointer actuating lever as theend 58 thereof moves up the incline seen between the lines f and g. As the back rest moves back, as by the action ofa spring l69. it clears the way for forward movement of the pointer which promptly takes place as the end of the lever 58 reaches the point indicated by the dotted line 7L. During'this interval-,the tail 52 of the feed finger lever has dropped into the depression 55, as hereinbefore explained, and the feed fingers are moved back to their rearward position where theyremain during a completion of the cycle of operation of the machine. Y At about the point denoted by the dotted Y line fl the chuck aw actuating stud 67 passes along asteep inclination of the lobe on the cam 68 and-the chuck jaws are rapidly opened to release the finished blank or screw cut during the preceding operation. i

' From the point indicated by the dotted line 7i the actuator 58 v-continues on up another steep inclination on the cam 59, thus causing the pointer to push the blank through the feed fingers and into the chuck 9 which has just been fully opened, this insertion of the blank in the cliuck jaws, as a matter of fact, taking place while said jaws are.` being .time'the tip 19. on the Abar 18 Vpasses down an inclination on the cam 2O to effect movement of the cutting tools .to the point for beginning a, cutting operation, andthe actuating lever L1Opasses up aninclined surface on the canrtl to movethe'cutting tools to- A ward thework for a cutting action. During this time the chuck actuating stud .67 has passed over the lobe ofthe cam 68 thus closing the chuck jaws on the new blank, this operation having takenrplace during movement of theactuator 58 from the line i to a pointindicatediby the dotted line j, from which latter point the camY 59 inclines slightly upward, thus moving the actuator 58 -to operate the pointer to point the blank. During this operation the actuating lever 40 has passed vup the inclined portion of the cam 41, this completing its first action, and further movement of the cutting tools toward the work'isfeffected by the action'of the cam plates -86, as here-inbefore described.

J ust after the tip 19 of the bar 18 passes the point indicated bythedotted line j an upward incllnation on the cam 2O is reached and the bar18 is operatedl to move the cutting tools'forward in a cutting action. As the beginning of this cutting action takes place at the Vh eel of the threadthe forward movement of said cutting tools begins during the action ofthe pointer to point the blank and before the cutting tools reach the 'point of the blank, 1n fact, just after they starttheir forward movement at about the point indicated by the dotted line 7c. ,When the actuator 58 reaches a point indicated by the dotted line Ic it passes quickly downan inclined'surface on the cam 59, thus moving the pointer to the backward limitof its play where such pointer remains luntil again advanced by the lirst upward inclination on the lobe of the cam 59, as hereinbefore described.

From this point on all of the parts remain in the positions `heretofore explained, with the exception of the bar 18, which is reciprocated bythe cam 20, and theactuating lever 40 which is operated to rapidly movev the toolsinto position to be engaged with the blank by the cam plates 35 and 36, this completing 'one' cycle of operationof the machine.

In the arrangement herein shown the cams on'thecam shafts 13, and especially the cam 59,vv are so formed as to'enable certain operations to be performedduring a single rotation of the shaft 21 bearing the traversing :cam 20. By'this arrangement the capacity of the machine as to production is materially in creased as the successive operations of 4different cam members, and parts operated thereby, follow one another immediately and without the necessity of waiting for the cam' 20 Y before set out resides in the arranvemento'f the driving gear for the cam shaft 13 and which is secured to said shaft. lt often is desirable to change the relative positions of the cams on the cam shaft 13 circumferentially or, in other words radially with vrespect tothe circumferential or radial position of other parts of the machine. This may be readily accomplished when such change requires a radial movement equal to the width of a gear tooth, but a diculty is encountered when the change is such as to require a movement of the cams to an extent of a fraction only of the width of a gear tooth. We have overcome this difliculty by so arranging the gear 7() that any amount of change radially, no matter how small, with respect to the shaft 13 may be obtained. To this end a gear plate 7l is keyed to the shaft 13 and the gear 70, in the form of a gear ring and having a liange 72, is secured to the plate by a bolt and slot connectiomas herein shown bolts in the plate being entered int-o' slots 73 in the flange 72 and as shown in Figure l of the drawings.

In accordance with the provisions of the patent statutes we have described the principles of operation of our invention, together with the device which we now consider to represent the best embodiment thereof; but we desire to have it understood that the device shown is only illustrative and that the invention may be carried out by other means and applied to uses other than those above set out.

We claim- 1. A screw making machine including means for holding and rotating a screw blank, a pluarlity of cutting tools positioned to effect simultaneous cutting action along the same groove in said blank, a tool post.

support, a cutting tool post fast to said support, a. cutting tool post supported on but Y. movable independently of said support,

means for rocking said support to engage a tool on one of said posts with the blank, means for engaging the tool on the other post with said blank, means for securing the last named post to said support for movement of said post away from the blank by the rocking movement of the support, and means for imparting relative movement to said support and blank lengthwise of the latter.

2. Screw making machine including means 3. 1,screw Y making mac for',holding. androtating a. screw-blanlnv a i plurality of, cutting'ltools positioned t0 ,act

inasimultaeus putting Operation @lengths blank, @112001. Poel Support. a cutting wel SPiOSl s fastto Said support, a :utting tool lpost supportedln tumorale .independante sind 4support, means/for 'rorikingi saidl suppogrtfto engage atool on one `of said posts with the blank, .means for engaging the .tool @the oEtlierposty with-said` blank, means for connecting the llast namedk postv with ,saidlsupportjfor movement of said post, away from the blank by the rocking movement of Athe support, and` Qmeans for imparting relative movement to said"l support and the rblank lengthwise ofthe latter.`

tool supporting bar, a ,tool -postfsecuredto Said. leali,I a wel Post Invented forlrolckee movement on .s,aid b ar, :a frame mounted for rocking movement onfsaidl bar, a foam. plate secured to sai'dba'r inthe path of movement of a projection extending laterally from .the

post movably ,mounted on thevbar, a cam plate '90 supported.. on Vsaid frame the path of'movement of a projection frOinsaid bar, means to Leffect lengthwise movement of said tool bar, and meansfor actuating said frame to simultaneously move both of said posts away from said blank.

t. A screw making machinev including means for holding and rotating a screw blank,

hine a a tool supporting bar, a tool post secured to i said bar, a tool post movably mounted on said bar, a frame mounted for rocking movement on said bar, cam plates located on op posite sides of thel axis of said frame, one of said plates being located in the path of movement of a projection from said bar and the other cam plate being located in the path of movement of a projection from the post movably mounted on the bar, means for holding both of said projections in contact with said cam pla-tes, and means for causing endwise movement of said bar. f

5. A screw making machine including a lfixture, a presser bracket supported by said fixture, a presser pivotally mounted in said bracket, means for swinging said presser on i its pivot to engage it with said plates thereby to effect rocking movementofsaid lix- 7. A screw making machine including av chuck for holding a blank, a cutting tool,

means for traversing said tool' along vsaid blank, means for supporting a blank in said chuck, a pusher, means for advancing the pusher to a point adjacent to said blank supporting means While supporting a`blank,

means for haltingvthe movement of the pusher, means for moving the supporting means and for placing ablank n front of 'said' pusher duringV said halt, means for advancing the pusher to place the blank in said chuck, and means for retracting said pusher.

8. A screwimaking machine including a ychuck for holding a blank, a cutting tool,

means for traversing said tool along said blank, means for positioning a blank in front of said chuck, a back rest for 4a blank, a

pusher, means for advancing the pusher `to a point adjacent to the back rest While supporting a blank, means for halting the movement of saidpusher, means for moving the back rest, means for advancing the pusher to place the blank in said chuck, and means for retracting said pusher. `l

' QREUBEN S. Y CROSBY.

CHARLES W. SPONSEL. 

